The present invention relates to an apparatus for coiling wire. More particularly this invention concerns a coil-laying device for such an apparatus.
Wire or rod (hereinafter termed xe2x80x9cwirexe2x80x9d only) is formed at high speed in a rolling or drawing mill and is delivered in straight condition to a coiler that forms it into a succession of large-diameter turns that it deposits on a surface, normally a conveyor of some type. Thence the coiled wire is moved through subsequent treatment steps such as heat treatment, descaling, pickling, or simply cooling. It is critical that the wire be deposited in uniformly shaped and spaced coils so that the subsequent treatment stage is effective.
The typical coiling system has a head fitted with a so-called laying tube twisted in three dimensions and having an intake upstream end opening axially in line with an axis about which the tube is rotated and a downstream output end which opens at a location radially offset from the axis and is directed generally tangentially. The straight wire is fed into the upstream end of the laying tube as it is rotated about its axis so that as the wire passes through the tube it is bent into an arcuate shape.
On exiting the laying tube the wire typically enters a helicoidal groove of a coil-laying device as described in British patent 1,175,402 and German patent document 1,291,716 of Bollig that rotates jointly with the head. This coil-laying device is a generally cylindrical structure formed with a helical or helicoidal passage through which the coiled wire is lead to set in the wire the desired shape. On leaving the coil-laying device the wire falls in a neat succession of turns on a belt or chain conveyor.
In EP 0,554,976 of Shore a system is shown where the wire is shaped on a drum having a helical and radially outwardly open groove formed between turns of a helical and radially outwardly projecting ridge or wall. This system is advantageous in that it allows the wire to be cooled relatively easily, and is particularly easy to load and service.
Practice has shown that the ability to influence the cross section and surface quality of the wire drawn through the grooves of the coiling device is very limited and in addition when wire diameter changes the device has to be replaced with one having an appropriately dimensioned groove. This is fairly expensive and difficult and entails considerable down time for the machine.
It is therefore an object of the present invention to provide an improved coiling device.
Another object is the provision of such an improved coiling device which overcomes the above-given disadvantages, that is which is of simple construction and that serves for better guiding the wire, especially at its leading and trailing ends.
A coil-laying device has a body having a generally cylindrical outer surface centered on and rotatable about an axis and wall structure forming on the surface a radially outwardly open groove having an intake end, a center, and an output end. The groove has according to the invention an axial dimension that decreases from the intake end to the center and that increases from the center to the output end.
The groove has an angular dimension of about 360xc2x0 and the center is located about 250xc2x0 from the output end, so that the center is spaced between 0xc2x0 and 110xc2x0 from the intake end.
Furthermore according to the invention the groove is defined between walls that taper together between the intake end and the center at a predetermined angle and that diverge from the center to the output end at a larger angle.
It has been found that such a laying device can be used without difficulty on wire of different caliber. Furthermore whipping of the trailing wire end is largely eliminated by the tapering/diverging shape of the groove. The intake end, that flares upstream, is ideally dimensioned to receive the starting end of a new wire so that alignment problems with the outlet of the laying tube are largely eliminated.